Squalane, obtained from natural sources, is one of the more common moisturizer agents used in dermatological preparations and is useful as a base oil for cosmetics. However, the production is low, the price is high, and the quality is not uniform. These problems make it desirable to find a squalane substitute.
C.sub.4 olefin polymers of a number average molecular weight range of from about 100 to about 4,000 g/mol are desirable for use in cosmetics and antiperspirants. The molecular weight range assures compatibility with many of the components found in these preparations. However, these C.sub.4 olefin polymers are normally light colored and carry an oily to pungent odor, both of which are undesirable in cosmetics and antiperspirants. While these characteristics may not be significant in industrial applications, such characteristics render the C.sub.4 olefin polymers unfit for more sensitive uses, such as cosmetics and antiperspirants, which require an essentially colorless and odorless product. As a topical application, a cosmetics and antiperspirants cannot have, or develop, offensive odors even though the preparation may contain perfume to add a pleasing fragrance.
Hydrogenation to produce a saturated compound of C.sub.4 olefin polymers, such as polybutene polymer, is taught in U.S Pat. No. 3,100,808 (fully incorporated herein by reference), to improve the color and odor of the resulting saturated polymer. However, although the hydrogenation process may reduce the odor and color in the C.sub.4 olefin polymers, the hydrogenated polymer can still contain odor-causing compounds, such as aldehydes, ketones, esters and peroxides.
U.S. Pat. No. 4,061,780 (Yoshida, et al.) teaches purification of C.sub.4 olefin polymers for use in cosmetic applications wherein a liquid C.sub.4 olefin fraction is polymerized in the presence of a catalyst. The polymerized reaction product is fractionally distilled to obtain a fraction having a boiling point range of from 120.degree. C. (248.degree. F.) to 200.degree. C. (392.degree. F.) at 1-2 mmHg to remove compounds having a molecular weight of less than about 250 g/mol and compounds having a molecular weight of more than 600 g/mol. The resulting fraction is hydrogenated and deodorized by steam distillation under reduced pressure, treatment with activated carbon, solvent extraction, or by a combination of steam distillation, treatment with activated carbon and solvent extraction. The initial distillation of the C.sub.4 polymer fraction is taught as removing compounds which can easily oxidize to form odorous compounds. This procedure is an economically costly commercial process.
Japanese Kokai Patent No. Sho 60[1985]-124602 discloses a manufacturing method for butylene polymer in the molecular weight range of 100-300 g/mol. The polybutene polymer is not hydrogenated. The polybutene is treated with a silicon-alumina adsorbent to decrease odor in the polymer for applications such as insecticide solvent or copier solvent.
U.S. Pat. No. 4,923,961, fully incorporated herein by reference, discloses deodorized polymers of C.sub.4 olefins that demonstrate an improved storage and color stability at temperatures of up to 200.degree. F. for extended periods. The C.sub.4 olefin polymer is hydrogenated and deodorized by nitrogen stripping to remove a portion of the hydrogenated product and by contacting the stripped product with attapulgite clay in a ratio of product to clay of 1:1 to 10:1. However, there is a large product loss, up to 24 percent, when the hydrogenated, nitrogen stripped polybutene polymer is deodorized with attapulgite clay. Further, regeneration and reuse of the attapulgite clay is not a viable alternative. Therefore, it would be advantageous to provide a method of manufacturing a deodorized polybutene polymer that reduces product loss and that includes the ability to regenerate and reuse the material used in the deodorizing step.
Accordingly, it is an object of the present invention to provide an improved process for production of hydrogenated deodorized polybutene polymer.
It is another object of the present invention to provide a process for the preparation of deodorized substantially saturated polybutene polymers of a number average molecular weight of from about 100 to about 4,000 g/mol wherein the polybutene polymers are substantially free of odor-causing compounds such as aldehydes, ketones, esters and peroxides, and are suitable for replacement of squalane, fatty esters, and other moisturizing agents used in cosmetics and antiperspirants.
It is still a further object of the present invention to provide a process that can be in batch or continuous mode, that is not complex in operation, that uses readily available process equipment, and that includes an adsorption medium that is easily regenerated such that the adsorption medium can be reused in future deodorizing processes.